/node_modules/babel-polyfill/node_modules/core-js/library/modules/_math-sign.js

1// 20.2.2.28 Math.sign(x)
2module.exports = Math.sign || function sign(x) {
3  // eslint-disable-next-line no-self-compare
4  return (x = +x) == 0 || x != x ? x : x < 0 ? -1 : 1;
5};